Live ORACLE

DECLARE
 emp  EMPLOYEE_TYP; -- emp is atomically null

BEGIN
 IF emp IS NULL THEN
   dbms_output.Put_line('emp is NULL #1');
 END IF;
 IF emp.employee_id IS NULL THEN
   dbms_output.Put_line('emp.employee_id is NULL #1');
 END IF;
 emp.employee_id := 330;
 IF emp IS NULL THEN
   dbms_output.Put_line('emp is NULL #2');
 END IF;
 IF emp.employee_id IS NULL THEN
   dbms_output.Put_line('emp.employee_id is NULL #2');
 END IF;
 emp := Employee_typ(NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,
                     NULL,NULL,Address_typ(NULL,NULL,NULL,NULL));
 -- emp := NULL; -- this would have made the following IF statement TRUE
 IF emp IS NULL THEN
   dbms_output.Put_line('emp is NULL #3');
 END IF;
 IF emp.employee_id IS NULL THEN
   dbms_output.Put_line('emp.employee_id is NULL #3');
 END IF;
EXCEPTION
 WHEN access_into_null THEN
   dbms_output.Put_line('Cannot assign value to NULL object');
END;
/  

emp is NULL #1
emp.employee_id is NULL #1
emp is NULL #2
emp.employee_id is NULL #3

PL/SQL procedure successfully completed.

Null Objects in a PL/SQL Block